Columbia Care - Riverhead is By Appointment Only! Columbia Care is proud to have four Medical Marijuana Dispensaries open in New York! We are the premier provider of medical marijuana services and pharmaceutical-grade products to qualifying patients in New York and throughout the United States. Our mission is to improve and revitalize lives and communities through partnership, research, education and the responsible use of our products as a natural means to alleviate symptoms and improve our patients’ quality of life.